Electric power conversion systems – Current conversion – Having plural converters for single conversion
Reexamination Certificate
2002-04-12
2004-06-01
Riley, Shawn (Department: 2838)
Electric power conversion systems
Current conversion
Having plural converters for single conversion
C363S072000, C363S050000, C363S055000
Reexamination Certificate
active
06744647
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to power conversion apparatus and methods, and more particularly, to switching power converter apparatus and methods of operation thereof.
DC-to-DC power conversion is commonly achieved using switching power converter circuits. Switching power converter circuits often include one or more switching elements that selectively couple a DC power source to an inductor, such as the primary winding of a transformer, such that the inductor is periodically charged and discharged to produce DC output voltage. The DC output voltage may be regulated by controlling the switching frequency and/or duty cycle of the switching elements.
A common type of switching converter is the isolated flyback converter. A typical isolated flyback converter includes a switching circuit that is operative to apply a voltage across a primary winding of a transformer to develop a current in the primary winding in an “on” phase. After lapse of a time interval, the switching circuit then open circuits the primary winding in an “off” phase. During the off phase, a voltage is induced on the secondary winding of the transformer, causing a current to flow to a storage capacitor via rectifying action of an output diode coupled to the secondary winding. The switching circuit may have different configurations, including single-ended configuration and double-ended configurations. An example of a double-ended configuration is described at pp. 139-140 of
Switching Power Supply Design
, by Pressman, 2
nd
ed. (1998). Another type of DC/DC converter circuit using a three-part conversion cycle is described in U.S. Pat. No. 6,285,568 to Taurand.
Although conventional flyback converters may be effective, there is an ongoing need for improved power converter designs that have properties desirable for output paralleling and other applications.
SUMMARY OF THE INVENTION
In some embodiments of the invention, a power converter apparatus comprises an input port and an output port. A first inductor is coupled to the output port. A first switching circuit is coupled to the input port and the first inductor, and is operative to repetitively perform a cycle comprising a first state in which the first switching circuit couples the first inductor to the input port such that energy is transferred from the input port to the first inductor, a second state in which the first switching circuit short circuits the first inductor, and a third state in which the first switching circuit decouples the first inductor such that energy is transferred from the first inductor to the output port. A second inductor is coupled to the output port. A second switching circuit is coupled to the input port and the second inductor, and is operative to repetitively perform a cycle comprising a first state in which the second switching circuit couples the second inductor to the input port such that energy is transferred from the input port to the second inductor, a second state in which the second switching circuit short circuits the second inductor, and a third state in which the second switching circuit decouples the second inductor such that energy is transferred from the second inductor to the output port. The second switching circuit may operate such that the first and second states of the second switching circuit substantially coincide with the third state of the first switching circuit.
According to further embodiments of the invention, a multi-phase power converter apparatus includes an input port and an output port. The apparatus also includes a first transformer having a primary winding and a secondary winding, and a first switching circuit coupled to the input port and the primary winding of the first transformer. The first switching circuit is operative to repetitively perform a cycle including a first state in which the first switching circuit couples the input port to first and second terminals of the primary winding of the first transformer, a second state in which the first switching circuit couples the first terminal of the primary winding of the first transformer to the second terminal of the primary winding of the first transformer, and a third state in which the first switching circuit decouples at least one of the first and second terminals of the primary winding of the first transformer from the input port while decoupling the first and second terminals of the primary winding of the first transformer from one another.
The apparatus also includes a second transformer having a primary winding and a second winding, and a second switching circuit coupled to the input port and the primary winding of the second transformer. The second switching circuit is operative to repetitively perform a cycle including a first state in which the second switching circuit couples the input port to first and second terminals of the primary winding of the second transformer, a second state in which the second switching circuit couples the first terminal of the primary winding of the second transformer to the second terminal of the primary winding of the second transformer, and a third state in which the switching circuit decouples at least one of the first and second terminals of the primary winding of the second transformer from the input port while decoupling the first and second terminals of the primary winding of the second transformer from one another. An output circuit is coupled to the secondary windings of the first and second transformers and is operative to transfer energy to the output port from the secondary windings of the first and second transformers as the first and second switching circuits cyclically operate.
In still other embodiments of the invention, a power converter apparatus includes an input port and an output port. The apparatus further includes a transformer having a primary winding and a secondary winding, and a switching circuit coupled to the input port and to the primary winding. The switching circuit is operative to cyclically apply a voltage to the primary winding from the input port and to then decouple the primary winding to induce a voltage across the secondary winding. An output circuit is coupled to the secondary winding and operative to transfer energy to the output port from the secondary winding as the switching circuit cyclically transitions. The apparatus further includes a clamp circuit coupled to the primary winding and operative to limit a voltage developed across the primary winding when the primary winding is decoupled. The clamp circuit further includes a clamp voltage generator circuit operative to produce a clamp voltage output node thereof, the clamp voltage between a voltage at a first terminal of the input port and a voltage at the second terminal of the input port, and a current control circuit, e.g., a diode, coupled between the primary winding and the output node of the clamp voltage generator circuit.
Embodiments of the invention can provide several advantages over conventional flyback and other switching converter configurations. For example, by using a power conversion cycle including a “short circuit” interval in which energy is stored in an inductor, an additional degree of freedom can be provided over that provided by conventional “two-state” switching converter circuits. This additional degree of freedom can allow for relatively simple implementation of multi-phase converters, including multiphase converters with self-driven output synchronous rectifier circuits. The invention may be embodied as apparatus and methods.
REFERENCES:
patent: 4618919 (1986-10-01), Martin, Jr.
patent: 5291382 (1994-03-01), Cohen
patent: 5508903 (1996-04-01), Alexndrov
patent: 5796595 (1998-08-01), Cross
patent: 5844787 (1998-12-01), Fraidlin et al.
patent: 6285568 (2001-09-01), Taurand
Unitrode, “Low Power, Dual Output, Current Mode PWM Controller,” SLUS272A, Feb. 2000 pp.1-7.
Viswanathan et al., “Tri-State Boost Converter with No Right Half Plane Zero,” PEDS '01 Conference Proceedings, 2001, pp. 1-7.
Lambda Electronics Inc.
Myers Bigel & Sibley & Sajovec
Riley Shawn
LandOfFree
Parallel connected converters apparatus and methods using... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Parallel connected converters apparatus and methods using..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Parallel connected converters apparatus and methods using... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3302359